2 Questions: Carbonating a keg & 3 gallon recipes

[adamgm]

Hi all,
a follow up from my other thread.

I've never used a keg before, but I'm looking into getting a 3 gallon for smaller batches, currently trying to figure out how hard it is to find kits & recipes for this amount. Anyone have any good resources for this?

Anyways - I've read a lot of threads on conditioning beer in a keg at room temp after using enough C02 to "seal the lid" or "filling the headspace". Do most kegs have a valve that shows you when this has been achieved? If you are leaving the keg alone for a more extended period of time, might you have to hit it with more C02? How would you know if you needed to add it?

The chart that I'm reading seems to indicate that, at room temp, I'll be using pressures upward of 25 PSI, at room temp, but I'm not sure how long that's required for. I assume the only way to not over carbonate is through careful timing and correct pressures used?

 

[hotbeer]

You can easily scale recipes with recipe builder tools provided on Brewer's Friend and other places. I'm cheap though and use a freebee software called BrewTarget . If your recipe source provides the recipe in an XML tagged format, then you can directly import it into many homebrew recipe builders. This saves a lot of tedious keyboard entry. BrewDog is one of the breweries that provide XML tagged recipes for download.

Can't help you with the kegging questions though.

 

[emac813]

For kegging, I burst carbonate my kegs at 30psi for 24-30 hours. Then, purge the keg of the high pressure and reset to 10psi for serving. I use 8' beer line for the tap. Note that I do this around 42F in my keezer and it is my understanding that CO2 absorbtion is inversely proportionate to the temperature of the beer.. so if you are trying to carbonate at room temperature, it will take longer.

Understand that the beer will only become carbonated if you keep it hooked up to constant CO2 pressure. If you are planning to just seal it off with a burst of pressure and leave it at room temperature, you can use priming sugar in the keg and allow the yeast to naturally carbonate the keg at room temp over two weeks. Its like bottle conditioning but using one giant bottle so you can cut the amount of priming sugar in half.

 

[grampamark]

Scaling recipes is pretty simple. If your scaling a 5 gal recipe to 3 gal just multiply the amount of each fermentable by .6. Hops don’t scale linearly, in my experience. Going from 5 to 3 I’d suggest reducing the hop additions by 25%.

Conditioning in the keg can be done at least 2 different ways. First, you can condition by adding priming sugar, as you do when bottling. The only C02 needed then is enough to seal the lid. Pressure isn’t that critical; just fill the headspace with enough pressure to achieve a seal. You’ll know when to stop when you can no longer hear the gas entering the keg. The sound is hard to miss (even for an old guy like me who has been known to ask people to type louder so I can understand their posts better ). When the pressure in the keg equalizes with the pressure the regulator is set for the sound goes away. After a couple of weeks the beer will be carbonated, just as it would be in the bottle.

The other method requires keeping the beer under pressure, with the gas connected and the pressure set to the indicated chart pressure. You will have to pull a sample periodically to check the carb level. If you want to try to carb in the keg without the gas hooked up you will have to periodically refill the headspace, let the beer absorb the gas, pull a sample, repressurize the headspace, lather, rinse, repeat.

If you really want to carb in the keg at room temp I’d suggest conditioning with priming sugar. The other method involves too much trial and error. If you want to store the beer until there‘s room in your kegerator just pressurize the headspace and leave alone. Then carb it according to the appropriate chart pressure once it’s on tap.

 

[IslandLizard]

Most recipes scale linearly ingredients-wise. So to brew a 3 gallon batch from a 5 gallon recipe, use 3/5 of all ingredients.
The only thing you need to adjust for is the water volumes in your system (profile), and brew losses.

Water volumes:
They typically don't scale linearly. For example, if your boil off in a 5 gallon batch is 1 gallon per hour, it's likely going to be the same 1 gal/hr when brewing a 3 gallon batch using the same kettle and heat source. Boil off could become even higher in smaller batches due to more vigorous boils, so turn your heat source down accordingly. Generally you don't need (or want) a hard rolling boil, a mere simmer (gentle surface rippling) is plenty, and better anyway.

Brew losses:
They vary due to your equipment and processes. The main one would be wort loss, such as when transferring chilled wort from kettle to fermenter. How much wort you're leaving behind with the trub. If it's sizeable, or a relatively large amount, you may want to look into minimizing those losses.
For example, if a gallon of wort remains in the kettle with your trub, that represents 1/4 of all your wort in a 3 gallon batch (=wort in your fermenter). That's a sizeable amount and probably worth recovering most of it.

 

[adamgm]

Scaling recipes is pretty simple. If your scaling a 5 gal recipe to 3 gal just multiply the amount of each fermentable by .6. Hops don’t scale linearly, in my experience. Going from 5 to 3 I’d suggest reducing the hop additions by 25%.

Conditioning in the keg can be done at least 2 different ways. First, you can condition by adding priming sugar, as you do when bottling. The only C02 needed then is enough to seal the lid. Pressure isn’t that critical; just fill the headspace with enough pressure to achieve a seal. You’ll know when to stop when you can no longer hear the gas entering the keg. The sound is hard to miss (even for an old guy like me who has been known to ask people to type louder so I can understand their posts better ). When the pressure in the keg equalizes with the pressure the regulator is set for the sound goes away. After a couple of weeks the beer will be carbonated, just as it would be in the bottle.

The other method requires keeping the beer under pressure, with the gas connected and the pressure set to the indicated chart pressure. You will have to pull a sample periodically to check the carb level. If you want to try to carb in the keg without the gas hooked up you will have to periodically refill the headspace, let the beer absorb the gas, pull a sample, repressurize the headspace, lather, rinse, repeat.

If you really want to carb in the keg at room temp I’d suggest conditioning with priming sugar. The other method involves too much trial and error. If you want to store the beer until there‘s room in your kegerator just pressurize the headspace and leave alone. Then carb it according to the appropriate chart pressure once it’s on tap.

For kegging, I burst carbonate my kegs at 30psi for 24-30 hours. Then, purge the keg of the high pressure and reset to 10psi for serving. I use 8' beer line for the tap. Note that I do this around 42F in my keezer and it is my understanding that CO2 absorbtion is inversely proportionate to the temperature of the beer.. so if you are trying to carbonate at room temperature, it will take longer.

Understand that the beer will only become carbonated if you keep it hooked up to constant CO2 pressure. If you are planning to just seal it off with a burst of pressure and leave it at room temperature, you can use priming sugar in the keg and allow the yeast to naturally carbonate the keg at room temp over two weeks. Its like bottle conditioning but using one giant bottle so you can cut the amount of priming sugar in half.

It sounds like using priming sugar is the way to go, however there is something I don't understand; if the C02 seal using forced carbonation continuously gets absorbed by the beer causing new C02 to be added, why doesn't that happen with priming sugar?

Is there a downside to using priming sugar even if you're going to be using C02?

Is there a point where carbonation will be done when using forced carbonation where the gas can then be removed and the beer can be left similarly to beer carbonated with priming sugar? (I'm not sure if I'm misunderstanding something here).

 

[grampamark]

It sounds like using priming sugar is the way to go, however there is something I don't understand; if the C02 seal using forced carbonation continuously gets absorbed by the beer causing new C02 to be added, why doesn't that happen with priming sugar?

Is there a downside to using priming sugar even if you're going to be using C02?

Is there a point where carbonation will be done when using forced carbonation where the gas can then be removed and the beer can be left similarly to beer carbonated with priming sugar? (I'm not sure if I'm misunderstanding something here).

The C02 introduced to seal the keg when using priming sugar does get absorbed onto the beer. But, it’s a one and done situation. The headspace in a 5 gal keg which is filled with 5 gal of beer is about half a gallon. That volume of C02 won’t create much (as in an unnoticeable level of ) carbonation. The priming sugar carbs the beer.

If you carb with priming sugar and, subsequently, put the beer on tap, the only C02 required is enough to dispense the beer and maintain carbonation. That’s what the carbonation chart is for. The pressure is set for the serving temp and desired level of carb and that level is maintained until the keg is empty.

When the beer is carbed and on tap the gas must remain connected to maintain the carb level. You can disconnect the gas between pours but when you reconnect it the gas will boost the headspace pressure back to the previous level. The only good reason to disconnect the gas is if one is planning to be gone for a few days, or weeks. Leaving the gas hooked up for an extended, and unattended, period of time is how one discovers very small leaks in the system. I would be willing to bet that virtually every member of this board who kegs can relate to that.

 

[bwible]

Hi all,
a follow up from my other thread.

I've never used a keg before, but I'm looking into getting a 3 gallon for smaller batches, currently trying to figure out how hard it is to find kits & recipes for this amount. Anyone have any good resources for this?

I’ve been brewing 3 gallon batches for years.
I use my brewing software and create recipes myself or scale 5 gallon recipes. I calculate all my recipes as collect 4 gallons boil down to 3.5, 3.5 goes into fermenter so that I actually get 3 gallons of finished beer when all is said and done.

A good starting point for converting 5 gallon recipes to my format is just to multiply everything by .7 (3.5/5) You will run into some rounding errors and then you just have to tweak everything using whatever software you have.